To quantify variation in Plasmodium infection within and among the Kanyawara chimpanzees, DNA was extracted from fecal samples and screened for malaria parasites using a single genome amplification (SGA) strategy via nested PCR, which targeted a 956-bp segment of the apicomplexan cytochrome B (cytB) mitochondrial gene as described previously3,7. The gene discussed is MT-CYB; the disease is malaria.